Active headrests with selective delayless subband adaptive filters in an aircraft cabin

Abstract Active noise control (ANC) systems try to attenuate noise by generating local zones of quiet. In this paper local ANC systems in a relevant environment are investigated, usingry conditions derived from environments like cars, planes or trains. The experimental setup consists of a wooden aircraft cabin mock-up and an active headrest system using two actuators (loudspeakers) and two sensors (microphones) placed in a headrest to create individual local zones of quiet at the ears of the occupant. Various concepts for active headrest systems are taken into account, such as multichannel controller concepts, virtual sensing techniques and delayless subband adaptive filters, focusing on the delayless subband adaptive filters. Based on these studies a new active headrest system is proposed, that is capable of generating a 10 dB zone of quiet for different non-stationary broadband disturbances, while compensating head movement. Using a selective delayless subband adaptive filter and off the shelf microphones and loudspeakers, the overall hardware demand is kept to a minimum allowing for a low cost application.